(a) Technical Field of the Invention
The present invention is related to a bike brake shoe molding structure, and more particularly, to one wrapped with a metal base.
(b) Description of the Prior Art
In the prior art, a bike brake shoe is injected in a molding structure containing a base wrapped with rubber material. Referring to FIG. 1 of the accompanying drawings, a brake shoe 1, a disk 11 of a metal base 10 is integrated by pivoting to a rod 12 before being placed into a die to be injection molded with glue solution for a bike brake shoe provided with a fixed rod. As illustrated in FIG. 2, a brake shoe 2 is first having a metal nut 22 fixed on the inner side of a metal disk 21 before being placed die to be injection molded with glue solution for a bike brake shoe provided with a fixed rod and a threaded hole 221 reserved for connecting to a threaded rod. Now referring to FIG. 3, a brake shoe 3 provided with auto inching function is characterized by that a metal adjustment base 33 is separately placed in a reserved hole 32, and is the hole 32 is then retained by a rubber filling block 34 so that a local displacement by rotation is achieved when the adjustment base 33 is released by loosening a bolt inserted through a screw hole 331 on the adjustment base 33. Accordingly, a braking surface 35 can be easily inched to stay flushed with the edge of the rim of the bike to have the adjustment base screwed in position to achieve the optimal braking effect. However, a hole 32 must be reserved for the brake shoe 3 to accommodate the adjustment base 33 to rule out the possibility of a simple production. Furthermore, the mounting of the filling block 34 only makes the assembly more complicate, and it may cause safety concerns since the filling block 34 may fall off due to the abrasion and vibration after a given time.
Among all those three types of braking shoes described above, the third one, i.e. the braking shoe 3, is the most practical and popular since it allows easy inching adjustment to stay flushed with the edge of the rim of the wheel. The present invention is related to an improved structure of the braking shoe 3.